The American singer-songwriter forgot the lyrics in the second verse and had to pause to regain her composure.
"I apologize. I'm sorry, I'm so nervous," Smith said, asking the orchestra to start over.
The audience in Stockholm's Concert Hall, many dressed in formal attire, clapped to support Smith as she tried anew.
She appeared to draw a blank again in the third verse, but only briefly, and finished the song with an emotional performance that left some in the crowd misty-eyed.